Monitoring dengue fever transmission

Dengue fever is a mosquito-borne viral disease caused by the dengue virus. Currently our understanding of how viral, ecological, environmental, and climatic factors affect disease transmission and outbreaks is limited. This carries the risk of disease introduction to non-infected areas including Europe.

Unfortunately children are the most affected group in endemic countries both in terms of incidence and severity. This demonstrates the urgent need for effective control strategies to protect children. To prevent spread of dengue, the EU-funded 'Innovative tools and strategies for surveillance and control of dengue' (DENGUETOOLS) project has brought together leading experts in the field.

As a first step, the consortium set up a laboratory-based surveillance system in Sri Lanka, which includes hospitals, outpatient settings and households. Thousands of samples were analysed by polymerase chain reaction for the presence of the virus, including field-collected adult mosquitoes. Additional assays were also developed for point-of-care detection of dengue in endemic areas.

As an intervention against dengue transmission to school children, scientists proposed the use of insecticide impregnated uniforms. However, the repellent efficacy drops upon repeated washing indicating the need for further optimisation.

Considerable part of the project is dedicated to the understanding of vector density, capacity and the preferred breeding sites. In various European countries, the consortium studied the impact of insecticidal aerosols on mosquitoes. They are working on associating temperature fluctuations with the risk of a dengue outbreak. Ongoing work to evaluate the risk of transporting dengue should complete the disease risk mapping.

Using a well-designed population-based system, the DENGUETOOLS initiative proposed to monitor the spatial and temporal distribution of dengue. This is central for warning against epidemic transmission and identifying the priority areas for intervention. Furthermore, the generated predictive models and maps should help policymakers in Europe to better prepare for and control dengue in the future.